1 files changed, 19 insertions, 0 deletions
diff --git a/spec/ruby/core/bignum/minus_spec.rb b/spec/ruby/core/bignum/minus_spec.rb
new file mode 100644
index 0000000000..754ef7fa42
--- /dev/null
+++ b/spec/ruby/core/bignum/minus_spec.rb
@@ -0,0 +1,19 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+describe "Bignum#-" do
+  before :each do
+    @bignum = bignum_value(314)
+  end
+
+  it "returns self minus the given Integer" do
+    (@bignum - 9).should == 9223372036854776113
+    (@bignum - 12.57).should be_close(9223372036854776109.43, TOLERANCE)
+    (@bignum - bignum_value(42)).should == 272
+  end
+
+  it "raises a TypeError when given a non-Integer" do
+    lambda { @bignum - mock('10') }.should raise_error(TypeError)
+    lambda { @bignum - "10" }.should raise_error(TypeError)
+    lambda { @bignum - :symbol }.should raise_error(TypeError)
+  end
+end